Hard working students ask for help from experts to solve biology problems

Both parents have a positive probability of AA and a positive probability of 3 4 * 3 4 = 9 16, and a probability of both being negative is 1 4 * 1 4 = 1 16

The probability of one positive and one negative is 1-9 16-1 16 = 3 8. This is easier to understand.

We use AA and AA for Rh positive, and AA for negative, then.

A couple with rh positive blood type and a child with rh negative birth indicates that the couple's genotypes are aa and aa

Parents aa*aa

Children aa:aa:aa=1:2:1

The chance of having 2 more children is Rh positive and the other Rh negative is 3 4 * 1 * 4 = 3 16

It was not complete before, because there was no rule whether the child was positive or negative, so it was 3 16 * 2 = 3 8

This means that the first child is positive 3 4 chance * the second child is negative 1 4 = 3 16 plus the first child is negative 1 4 chance * the second child is positive 3 4 4 probability = 3 16 because there is no order relationship, so 3 16 + 3 16 = 3 8

Think of it this way, the couple is both heterozygous in genotype. Then the probability of giving birth to a positive is 3 4, and the probability of giving birth to a negative is 1 4;

Then they have two more children: one is Rh positive, the other is Rh negative with a probability of 3 16, one is Rh negative, and the other is Rh positive with a probability of 3 16, and the two together are 3 8.

There are two CO2 required for photosynthesis in plant B**, which is released by respiration and absorbed from the outside world.

That is, CO2 released by respiration + CO2 absorbed by the outside = total amount of CO2 required for photosynthesis.

And this question seeks the increase in "dry weight". Dry weight refers to "the total amount of glucose produced by light and action minus the amount consumed by respiration", i.e. "total amount of CO2 required for photosynthesis - CO2 released by respiration" = dry weight (i.e. CO2 absorbed by the outside world).

From the photosynthesis reaction equation, it can be seen that 1C6H12O6 corresponds to 6CO2, and the increase in glucose is x, which is conserved according to the mass.

It can be seen that 180:264=x:33 is obtained by solving the equation.

Through this question, it can be seen that the net photosynthetic amount (dry weight) of plants is equal to the photosynthesis of CO2 absorbed from the outside world, if you ask the total photosynthetic amount, you still have to add the one released by respiration, that is, the total photosynthetic amount should be 180:264=x:

44 (44 is obtained from 11+33).

b、 。

The CO2 in the container decreased by 33mg per hour, indicating that the net photosynthesis was 33mg of assimilated CO2 per hour, according to the equation, 6 CO2 corresponded to one C6H12O6, and the increase in high glucose was xmg, 264:180=33:x, and x= was obtained.

So the answer is b.

When there is light, the amount of carbon dioxide is reduced by 33mg, and these CO2 are photosynthesized to accumulate organic glucose, and 6 molecules of CO2 correspond to 1 molecule C6H12O6, 6CO2---C6H12O6

So the answer b

B. The CO2 in the container decreases by 33mg per hour, indicating that the net photosynthesis is 33mg of assimilated CO2 per hour, 6 CO2 corresponds to a C6H12O6, and the increase of high glucose is XMG, 264:180=33:X, and X=.

So the answer is b.

From the first material, it can be seen that the cell types are diverse.

From material 2, it can be seen that the cell size is diverse.

Taken together, we can see that cells are diverse.

1. Cells are the basic units of structure and function of organisms, and organisms are (mainly) composed of cells.

2. The egg cell is the most important reproductive cell, (it not only provides 50% of the genetic material for the fertilized egg, but also provides material guarantee for the completion of fertilization and the development of the zygote), and the specialization of the cell structure determines its functional specialization.

The egg cell of an organism is much larger than other cells because of the large amount of nutrients (such as yolk, etc.) stored in the egg cell.

1. C (the needle should be pierced into the vein rather than the artery).

2, this is not a picture.

4) Arteries (capillaries are located between arterioles and venules, and blood flow is to: arterial capillary veins).

Blood and tissues exchange gas and nutrients (function of capillaries).

Answer: A

Combined with the title, according to the analysis of the figure, in Figure 1, the pH of the chloroplast matrix = 4, and the ph of the thylakoids = 7 (the pH of the chloroplast matrix is less than the pH of the thylakoids), when both of them become pH = 4, ATP cannot be produced (as shown in Figure 2). Then from Figure 2 to Figure 3, that is, when the chloroplast matrix is pH = 8 and the thylakoids are pH = 4, ATP can be produced. This means that the condition for the production of ATP is that the pH of the chloroplast matrix is greater than that of the thylakoids.

i.e. the thylakoids of chloroplasts should be composed of hydrogen ions higher than the chloroplast matrix.

Light is necessary for photosynthesis, but this experiment is an isolated chloroplast, and there is an original substance, so light is not necessarily needed.

C, obviously C is not right, they all said that the pH is the same.

(1) If you immediately use a match with embers to test the mouth of the 1 4 good test tube after putting in the item, what will happen to each test tube?

Match No. 1 (re-ignited), Match No. 2 (re-ignited), Match No. 3 (unchanged), Match No. 4 (unchanged). Explanation: MNO2 is a strong oxidant, and catalase in fresh pig liver can decompose hydrogen peroxide into water and oxygen, and oxygen can rekindle matches.

H2O2 also has a small amount of decomposition under normal circumstances, so whether the number is unchanged or slightly brighter is considered at your own discretion.

2) If No. 1, No. 2, No. 3, and No. 4 are all controls set to verify a certain characteristic of the enzyme, which number is not scientific, and how can it be improved?

4) The number is not set scientifically, and the method of improvement is (to change the temperature to 37 degrees). Explanation: The experiment should control the variables, that is, generally speaking, there can only be one variable in the comparative experiment, and the 4th becomes 0 degrees, and the substances added are also different.

3) To prove that the activity of the enzyme is affected by the pH, and add a No. 5 tube, please add:

No. 5 test tube should be added (fresh pork liver, an appropriate amount of hydrochloric acid (acidic) or an appropriate amount of sodium hydroxide (alkaline)) PS: do not add both, it is impossible to verify the effect of acidity and alkalinity at the same time.

The temperature of tube No. 5 should be controlled at (37 degrees) Explanation: Because tube No. 2 is 37 degrees.

If you test the mouth of tube No. 5 with a match with embers, you will rekindle but the flame will not be as large as that of tube No. 2. Explanation: Too much acid or too much alkali will affect the activity of the enzyme, the activity of the enzyme is reduced, and the amount of hydrogen peroxide decomposed is naturally less.

You set up test tube No. 5 and test tube (2) as a set of comparative tests to complete the proposition (3) above, and the conclusion of this set of experiments is (see the explanation of question 3 for details, I wrote.) ）

(1) Re-ignition Re-ignition, the flame is larger, no obvious reaction, no obvious reaction.